DE 10 2004 002 539 A1 discloses a bending method and a bending device for bending elongate profile bodies, in particular for bending pipes. In this context, an initially straight pipe is transported by means of a drive unit comprising rollers which are driven in opposite directions. This pipe is bent by means of a pair of driven bending rollers and a bending roller which is adjustable in a direction of advance and perpendicular thereto, and which can also be rotated about an axis which extends substantially parallel to the axis of advance. So as to make three-dimensional bending of the pipe possible, a rotation unit is provided, by means of which the pipe can be rotated about the axis thereof during the advance.
However, the use of a conventional method of this type and a conventional device of this type may be found to be unfavourable if the profile which is to be bent in three dimensions in space is to be produced by a continuous method, for example by extrusion, in a production step upstream from the bending. Rotation of the profile about the axis of advance thereof, as provided in accordance with the conventional method for three-dimensional bending, requires a portion which is to be bent of the profile to be separated in advance from the continuous strand. Further, the conventional bending method and the conventional bending device are disadvantageous for irregular, non-circular profile cross-sections—for example for rail-shaped or channel-shaped profiles—because of the aforementioned requirement to rotate the profile, among other reasons.
Further, the use of driven drive and bending rollers, such as are provided in the conventional device, can lead to visible traces being left behind, during the bending process, on an outer surface of the profile which comes into contact with the rollers. If the outer surface of the profile will subsequently be a visible surface, at least in regions, reductions of this type in the surface quality are undesirable for aesthetic reasons.
This is a situation which would merit improvement.